PRECIOUS STONES. 



641 



South " (Pj.'i carats), which was purchased by the 

 Miiliarajuli t'f Haroda for $400,000 at' t lie- 

 World's Fair held in 1'uris in 1807. It also 

 rivals UK; " Florentine," which weighed \:;:;* 

 earals and was sold for 2,(KK>,U()0 florins, but it 

 is only a long double rose or drop, and not a 

 brilliant. 



Du Toit 1," which weighs 244 carats in the 

 rough, the " Great Orange " weighs 110 carats, 

 the Porter Rhodes," a perfectly white stone of 

 l.V) carats before cutting, and many other large 

 stones have been found in the Kimberley mines. 

 In .March, 1888, there was found in the Do 

 I Jeers mine an octahedral crystal of diamond 

 weighing 42HJ carats. It is not entirely white, 

 having a slight yellow tinge, and was valued at 

 3,000. 



More diamonds of over 75 carats after cutting 

 have been found since the African mines were 

 opened than were known before. Thirty-eight 

 million carats of diamonds, weighing over 7$ 

 tons, have been found here. In the rough their 

 aggregate value is 50,000,000, and after cutting 

 100,000,000, or nearly $500,000,000 more than 

 the world's output during the two preceding 

 centuries. Of the whole yield, not more than 8 

 per cent, can be said to be of the first water. 

 12 per cent, of the second water, and 25 per 

 cent, of the third, while the remaining 45 per 

 cent, is called boart, a substance that when 

 crushed to a powder is used for cutting hard 

 substances and engraving. This must not be 

 confounded with the caroon (carbonado) found 

 in Brazil, an uncrystalline form of the diamond 

 which is used in drills and has never been found 

 in South Africa, and is worth from 6 to 10 

 times as much as boart. Nothing will cut glass 

 but the natural crystal edge of a diamond. Glass 

 will scratch glass, while even a cut diamond or 

 a cleavage face will only produce a scratch, al- 

 though almost every finder of a curious pebble 

 is sure that it will cut glass like a diamond. 



Brazil. The diamond mines at Salabro, near 

 the river Pardo, Brazil, known as the Cana- 

 vieiras, were discovered in 1882 by a miner who 

 had worked in the earlier and now nearly ex- 

 hausted mines. The gems were found at a 

 depth of about two feet in red gravel, are fine in 

 quality, and are remarkable for their purity and 

 whiteness, the crystals beingsuch that scarcely 

 any cleaving is necessary. When the Brazilian 

 mines were discovered, the stones were sent to 

 India to enter the European markets in Indian 

 wrappers. Similarly, diamonds from Africa 

 were sent to Canavieiras to be shipped to Europe 

 as the product of that mine. Other Brazilian 

 mines have been only slightly worked of late 

 years. The black diamond, carbonado, or boart, 

 used for diamond drills, saws, etc., has fluctuated 

 in price very much. 



Specimens of that very curious form known 

 as " round boart," found only in Brazil, were 

 shown at the Amsterdam exhibition of 1 VS 'J. 

 They were perfect spheres, the result of a multi- 

 ple twinning of the cubic form of the diamond. 

 In order to determine its hardness, one of these 

 was cut into the rude outline form of a brilliant 

 by Tiffany & Company, who placed its table on 

 an iron polishing wheel with a little diamond 

 dust, revolving at the rate of 2,800 a minute. 

 The circumference of that part of the wheel on 

 VOL. xxxin. 41 A 



which the diamond was placed was about 2^ feet. 

 It remained there ten hour* a day for one hundred 

 days, so that the surface that traveled over this 

 diamond amounted to 80,000 mJes. Four and, 

 at times, K pounds of pre.-siire were added to the 

 usual 2% pound.- and li.j pounds of the clamp- or 

 holder, while for a time 40 pounds extra wen- 

 added, cau.-ing the diamond to throw out scin- 

 tillations -everal feet long. The wheel was 

 plowed up and ruined, yet no polish was pro- 

 duced, and the diamond was only slightly ground 

 away. 



Australia. About 12,000 diamonds have been 

 found in the Tertiary gravels and recent drift 

 mar Hingera, in I nverell, Australia; also along 

 the Cudgegon river, 160 miles northeast of Syd- 

 ney, and in other districts. The colors are 

 white, straw, yellow, light brown, pale green, 

 and black. The largest stones found were cut 

 into gems weighing 3$ and 3 carats respectively. 

 A trial made by the Australian Diamond Min- 

 ing Company produced 190 diamonds, weighing 

 197f carats, from the washing of 279 loads of 

 earth. 



United States. The similarity of the South 

 African peridotite to a peridotite found in Elliot 

 County, Ky., led H. Carvil Lewis to suggest in- 

 teresting possibilities there, and John W. Pow- 

 ell, director of the United States Geological Sur- 

 vey, sent Joseph S. Diller and George F. Kunz 

 to examine the Kentucky peridotite. The asso- 

 ciated minerals were identical with the South 

 African, the pyrope garnet, ilmenite, biotite, and 

 pyroxene being present, but by analysis of the 

 inclosed carbonaceous shales from which it is 

 believed that the diamond is formed, it was 

 found that the Kentucky shale contained only 

 681 per cent, of carbon, while the South African 

 contained 35 per cent, and could be readily 

 ignited with a match. Hence, unless the peri- 

 dotite has penetrated the older and richer De- 

 vonian shales, the probability of finding dia- 

 monds there has been considerably lessened by 

 the investigation. A beautiful twinned hexoc- 

 tahedral diamond crystal of 4$ carats was found 

 in Dysartville, N. C., in June, 1886. A boy dis- 

 covered the " pretty trick," as he called it, at a 

 spring, and it was some time before it was sus- 

 pected to be a diamond. None of the associa- 

 tions of the diamond were observed at the spring, 

 therefore it is probable that the stone was car- 

 ried there by some miner who was washing up 

 his gold and failed to notice the shining crystal 

 among the " wash-up." It was of a faint gray- 

 ish-green tint, quite perfect as a gem, and would 

 make, when cut. a stone worth about $100. A 

 number of stones called diamonds have been 

 found at Brackettstown, N. C., but they have 

 proved on examination to be transparent zircon 

 or smoky quartz. 



Meteoric Diamonds. A meteoric .-tone 

 weighing about 4 pounds fell on Sept. 4, 1886, at 

 Novy Urej.Krasnoslobodsk, in theGovernment of 

 Penza, Siberia, in which M. Latchinoff and Jore- 

 feif discovered what they supposed to be dia- 

 monds of microscopic size. In an insoluble 

 residue small corpuscles showing traeesof polar- 

 i/ation were found, harder than corundum, and 

 having the density and othercharacteristiesof the 

 diamond. A small piece of the meteorite treated 

 with solvents gave a residue of 12 small trans- 



